At this point in time, I, too, think it's the Spanish teacher. The first Mole's name was Katherine. This one's name is Katie. Hmm... coincidence? Possibly.... She's so emotional and appears so "innocent" and "naive" that she'd make a great mole. Some people are trying too hard to act mole-like (like Elavia). Katie was able to sabotage the game in the Blueberry Game and yet appear like it wasn't her fault -- she was "tricked" into it. BUT, having said that, I will add that she does seem to be very visible for a mole. I would think that the mole would be someone who'd fly more under the radar. But, hey, it's all part of the strategy and using what people assume against them, right?
BTW, I could not stand the constant smirk that Lisa had on her face last night when Darwin and Katie were being informed about how they "fell" for the Blueberry Trick and the other two had been exempted. If they showed her disgusting "I'm-trying-to-contain-it-but-just-can't" smirk one more time I was going to scream!